//获取id，tagName
function getIdName(id, tagName) {

    if (tagName != 0) {
        return document.getElementById(id).getElementsByTagName(tagName);
    } else {
        return document.getElementById(id);
    }
}

function hdp(json) {
    var tiemr = null;
    var pd = 0;
    var index = 0;
    var that;
    var option = {
        li: "li", //默认值：默认用li包裹
        boxid: "", //最外面div  id
        imgid: "", //图片外面id
        optid: "", //opt外面id	
        an: "", //左右按钮id，用于移上显示和隐藏
        prev: "", //左边箭头id
        next: "", //右边箭头id
        ms: 1500 //多少毫秒切换一张
    }
    for (var i in option) {
        if (json[i] != undefined) {
            option[i] = json[i];
        }
    }

    var div = getIdName(option.boxid, 0);
    var imgs = getIdName(option.imgid, option.li);
    var lis = getIdName(option.optid, option.li);
    var an = getIdName(option.an, 0);
    var prev = getIdName(option.prev, 0);
    var next = getIdName(option.next, 0);
    var ms = option.ms;

    function lbt(that) {
        if (that >= 0) {
            index = that;
        } else {
            if (pd == 0) {
                index++;
            } else {
                index--;
                pd = 0;
            }
        }
        if (index >= lis.length) index = 0;
        if (index < 0) index = lis.length - 1;
        for (var j = 0; j < lis.length; j++) {
            lis[j].className = "";
            imgs[j].className = "";
        }
        lis[index].className = "on";
        imgs[index].className = "current";
    }
    imgs[index].className = "current";
    lis[index].className = "on";
    for (var i = 0; i < lis.length; i++) {
        lis[i].index = i;
        lis[i].onclick = function() {
            that = this.index;
            lbt(that);
        }
    }
    timer = setInterval(lbt, ms);


    div.onmouseover = function() {
        clearInterval(timer);
        an.style.display = "block";
    }
    div.onmouseout = function() {
        timer = setInterval(lbt, ms);
        an.style.display = "none";
    }
    prev.onclick = function() {
        pd = 1;
        lbt();
    }
    next.onclick = function() {
        pd = 0;
        lbt();
    }
}